Many electronic devices (e.g., desktop computers, laptop computers, mobile devices, and the like) include a keyboard as one of its input devices. There are several types of keyboards that are typically included in electronic devices. These types are mainly differentiated by the switch technology that they employ. One of the most common keyboard types is the dome-switch keyboard. A dome-switch keyboard includes at least a key cap, a layered electrical membrane, and an elastic dome disposed between the key cap and the layered electrical membrane. When the key cap is depressed from its original position, an uppermost portion of the elastic dome moves or displaces downward (from its original position) and contacts the layered electrical membrane to cause a switching operation or event. When the key cap is subsequently released, the uppermost portion of the elastic dome returns to its original position, and forces the key cap to also move back to its original position.
In addition to facilitating a switching event, a typical elastic dome also provides tactile feedback to a user depressing the key cap. A typical elastic dome provides this tactile feedback by behaving in a certain manner (e.g., by changing shape, buckling, unbuckling, etc.) when it is depressed and released over a range of distances. This behavior is typically characterized by a force-displacement curve that defines the amount of force required to move the key cap (while resting over the elastic dome) a certain distance from its natural position.
It is often desirable to make electronic devices and keyboards smaller. To accomplish this, some components of the device may need to be made smaller. Moreover, certain movable components of the device may also have less space to move, which may make it difficult for them to perform their intended functions. For example, a typical key cap is designed to move a certain maximum distance when it is depressed. The total distance from the key cap's natural (undepressed) position to its farthest (depressed) position is often referred to as the “travel” or “travel amount.” When a device is made smaller, this travel may need to be smaller. However, a smaller travel requires a smaller or restricted range of movement of a corresponding elastic dome, which may interfere with the elastic dome's ability to operate according to its intended force-displacement characteristics and to provide suitable tactile feedback to a user.